Process for producing a novel textured yarn

ABSTRACT

CONTINUOUS FILAMENTS OF THERMOPLASTIC MATERIAL ARE PROVIDED WHEREIN SUCH FILAMENTS CONTAIN A HELICOIDAL CURLING AND/OR A RESIDUAL TWIST COUPLE. THE FILAMENTS HAVE A CROSS SECTION WHICH IS SUBSTANTIALLY THE SHAPE OF A BEAN, SUCH CROSS SECTION VARYING SLIGHTLY ALONG THE LENGTH OF THE FILAMENTS. THE FILAMENTS ARE PRODUCED BY A PROCESS WHICH COMPRISES CREATING AN INITIAL TWIST IN AN INDIVIDUAL STRAND OR IN AN ASSEMBLY OF A NUMBER OF STRANDS HAVING A HIGH COUNT PER STRAND AND A SMALL NUMBER OF STRANDS PER ASSEMBLY, THERMALLY TREATING THE TWISTED STRANDS OR ASSEMBLY OF STRANDS, BLOCKING SUCH TWIST AT A POINT, AND SEPARATING THE SINGLE STRAND OR ASSEMBLY OF STRANDS AT SUCH POINT AND WINDING THEM UP. SUCH A PROCESS IS CHARACTERIZED IN THAT THE POINT OF SEPARATION OF THE YARN IS   LOCATED IMMEDIATELY AT THE OUTLET OF THE HEAT TREATMENT YARNS WHILE THE YARNS ARE STILL IN A PLASTIC STATE. THE APPARATUS NECESSARY FOR CARRYING OUT SUCH PROCESS COMPRISES A DELIVERY MEANS FOR PROVIDING THE YARN BY UNWINDING, MEANS FOR SEPARATING THE STRANDS OR ASSEMBLY OF STRANDS, MEANS FOR INITIATING THE TWISTING, MEANS FOR HEATING THE TWISTED YARN, AND MEANS FOR RECEIVING THE YARN. SUCH APPARATUS CAN ADDITIONALLY CONTAIN DRAWING MEANS.

Sept. 3, 1,74 BUZANQ R.- 28,150

PROCESS FOR PRODUCING A NOVEL TEXTURED YARN Original Filed Nov. 20, 19692 Sheets-Sheet 1 INVENTOR MICHEL BUZANO ATTURN EYS Sept. 3, 1974 M.BUZANO R0. 28,150

rnoczss FOR rnonucme A Naval, 'rax'nmzn mm! Original Filed Nov. 20, 19692 Sheats-Sheet 2 30 FIG. 5

mvmm

MCHEL BUZANO United States Patent Office Reissued Sept. 3, 1974 Int. Cl.noz 1/02 US. Cl. 57-151 TS 2 Claims Matter enclosed in heavy brackets[II appears in the original patent but forms no part of this reissuespecification; matter printed in italics indicates the additions made byreissue.

ABSTRACT OF THE DISCLOSURE Continuous filaments of thermoplasticmaterial are provided wherein such filaments contain a helicoidalcurling and/or a residual twist couple. The filaments have a crosssection which is substantially the shape of a bean, such cross sectionvarying slightly along the length of the filaments. The filaments areproduced by a process which comprises creating an initial twist in anindividual strand or in an assembly of a number of strands having a highcount per strand and a small number of strands per assembly; thermallytreating the twisted strands or assembly of strands; blocking such twistat a point; and separating the single strand or assembly of strands atsuch point and winding them up. Such a process is characterized in thatthe point of separation of the yarn is located immediately at the outletof the heat treatment yarns while the yarns are still in a plasticstate. The apparatus necessary for carrying out such process comprises adelivery means for providing the yarn by unwinding, means for separatingthe strands or assembly of strands, means for initiating the twisting,means for heating the twisted yarn, and mean for receiving the yarn.Such apparatus can additionally contain drawing means.

The present invention is directed to a novel textured yarn, a processfor producing the same, and apparatus for use in conjunction therewith.More particularly, the present invention is directed to such texturedyarn in which the same is characterized by a helicoidal curling and/orresidual twist couple, the same having substantially the shape of abean.

The method of producing textured yarns from artificial or syntheticthermoplastic material by twisting, fixing and untwisting has been knownfor a long time. Thus, yarns have been obtained with a helicoidalcurling and great elasticity from continuous yarns of artificial orsynthetic thermoplastic material.

Such yarns can be obtained continuously either by false twisting with afalse twisting spindle, or by driving the twisting back, by twisting twoyarns together, by thermally fixing the twisting, and then by separatingthe ends of the yarn, the equilibrium of the tensions being assured, forexample, by a parallelogram device, at the time of this separation.

Such yarns, produced as above and in accordance with the presentinvention, are eminently suitable for a wide variety of applications,the same being particularly suited in the production of hosiery. Thus,for example, when monostrand yarns are used in the production ofstockings this becomes a very expensive solution to the problem ofproducing a satisfactory stocking yarn.

It has also been known that elastic knits can be prepared fromnon-elastic yarns with a residual twist couple by alternately knitting arow of S twist yarn and a row of Z twist yarn. Such a solution to theproblem at hand as well as those discussed above are not entirelysatisfactory, however, because in addition to elasticity, a stockingyarn is required to have an agreeable touch and as flattering anappearance as possible.

To solve this problem, it has been suggested that yarns be used with anoncircular cross section, e.g., multilobular yarns. However, tests madewith such yarns have been disappointing, because their resistance tosnagging was not greater than that of ordinary stockings.

Accordingly, until the development of the novel product, process, andapparatus of the present invention no suitable solution to theatorenoted problems was developed. Such problems, however, have now beenovercome in accordance with the present invention whereby novelcontinuous filaments of thermoplastic material, characterized in thatthey comprise a helicoidal curling and/or a residual twist couple, areprovided. Such novel continuous filaments of the present invention havea cross sectional shape substantially that of a bean, i.e. kidneyshaped, and this shape varies slightly along the length of thefilaments. As indicated previously, it is the production of such novelcontinuous filaments which has eliminated the problems associated withthe production of a satisfactory filament for hosiery.

Accordingly, it is a principal object of the present invention toprovide a novel textured yarn, a process for producing the same, andapparatus used therein, which yarn, process, and apparatus haveeliminated the inherent deficiencies of the prior art.

It is a further object of the present invention to provide such a noveltextured yarn particularly suited for use in the production of hosierywherein such yarn is characterized in that the same comprises ahelicoidal curling and/or a residual twist couple, with a cross sectionsubstantially like that of the shape of a bean, varying slightly alongthe length of the product.

A still further object of the present invention comprises a novelprocess for the production of such continuous filaments of thermoplasticmaterial which comprises creating an initial twist in an individualstrand or in an assembly of a number of strands having a high count perstrand and a small number of strands per assembly, thermally treatingthe twisted strand or assembly of strands, blocking such twist at apoint, and separating the individual strand or assembly of strands atthis point and winding them, such process being characterized in thatthe point of separation of the yarns is located immediately at theoutlet of the heat treatment zone when the yarns are still in a plasticstate.

Yet a further object of the present invention relates to the apparatusfor carrying out such process, such apparatus comprising delivery meansfor providing the yarn by unwinding, means for separating the strands oryarns, means for starting the twisting, means for heating the twistedyarn, and means for receiving the yarns.

Still further objects and advantages of the novel textured yarn, processfor producing the same, and apparatug of the present invention willbecome more apparent from the following more detailed descriptionthereof.

A preferred yarn according to the present invention is capable of greatelongation. The same comprises a small number of strands, generally lessthan 5, each strand presenting a helicoidal curling and having at least2 filaments with a residual twist couple, and a cross sectionsubstantially the shape of a bean, such cross section varying slightlyalong the length of the yarn. In a preferred form, the yarn according tothe present invention comprises only 1 or 2 strands with a high count,advantageously more than 5 dtex per strand.

In accordance with the present invention the yarn can be prepared fromany suitable synthetic thermoplastic material. However, it is preferredin accordance with the present invention that the yarn be prepared fromconventional thermoplastic materials such as polyamides, i.e., nylon, orpolyesters, i.e., pIyethyleneterephthalate. Accordingly, such materialsare preferred in accordance with the present invention.

The textile product, according to the present invention, prepared fromthe above-described filaments can be woven, knitted or not woven. Inaccordance with a particularly attractive form, such textile product isadvantageously an elastic knit, particularly in the form of a stocking,alternately presenting a row of S twist yarn and a row of Z twist yarn.Besides its elasticity, such a knit is particularly remarkable by itsflattering appearance and pleasant touch.

The novel process for the production of such continuous filaments oryarns of thermoplastic material comprises creating an initial twist inan individual strand of thermoplastic material or in an assembly of anumber of strands, each strand having a high count, there being a smallnumber of strands per assembly; thermally treating the individualtwisted strand or twisted assembly of strands; blocking the twist at apoint; and separating the individual strand or assembly of strands atsuch point and winding them. Such process comprising the presentinvention is characterized in that the point of separation of theindividual strand or assembly of strands is located immediately at theoutlet of the heat treatment zone at a time when the yarn is still in aplastic state at a temperature substantially equal to that employedduring heat treatment,

By plastic state, it is meant that state in which the yarn is at such atemperature that it can be deformed, such temperature being less thanthe temperature at which the strands of the yarn stick together.

The assembly of strands or yarns having a high count per strand and asmall number of strands are those having a count similar to those yarnsnormally used for the production of certain hosiery articles such asstockings. Such assembly of strands or yarns are those which preferablycontain only a few strands per yarn or assembly, advantageously lessthan about 5 strands. Each individual strand is preferably one having ahigh count, preferably greater than 5 dtex.

The twist that is given to the individual strand or assembly of strands,i.e., yarn, depends somewhat upon the synthetic material that is used.However, it has been found in accordance with the present invention thatsuch twists can be up to twist saturation.

In accordance with the process of the present invention, there is nodilference whether the starting material comprises a multi-strandassembly or yarn which is subsequently separated into the elementalstrands making up the same after having given them a certain twist orthe starting material comprises several strands which are assembled in afirst phase by twisting and then separated.

As indicated previously, after the individual strand or assembly ofstrands has a twist created therein, the twisted assembly, i.e., yarn orstrands, is subjected to a thermal treatment. In accordance with apreferred embodiment of the present invention, the yarns or strands aredrawn continuously up line from the twist zone through the thermaltreatment zone such that the twist is blocked at a point located up linefrom such thermal treatment zone so that the initial ends are drawn in aslightly twisted or untwisted state.

The heat treatment temperature should be sufficient to permit thefurther fixing of the twist imparted to the yarn and the deformation ofthe initial section of the unit strands, but less than that which wouldcause their sticking. The best treatment temperature can vary, dependingon the effect desired and, in particular, whether it is desired to givemore or less curling. The same also depends on the length of the heattreating zone, which advantageously will be short in relation to thelengths of the zones of fixation of the processes of standardtexturation. For example, for yarns of Nylon 66 at texturation rates notexceeding 300 meters per minute, this length will be less than a meter,preferably between 20 and cm. In a general way, the temperature of theheating organ depends on the nature and length of this organ, the rateof pulling and the nature of the yarn.

It should be quite clear that the twist given to the strand or yarn atthe beginning of the operation can be kept constant during the course ofthe remainder of the process. However, in accordance with a particularembodiment of the present invention, special effects can be obtained byvarying the twist, for example, according to a pre-established andpre-set program. Similarly, the rate of drawing when utilized can vary,particularly when it is desired to produce a flake textured yarn.

In addition, it is pointed out that it is often possible to give anadditional slackening to the yarn or strands after the separation pointand before winding. This slackening may or may not be accompanied by asecond heat treatment depending upon the particular characteristics tobe given to the final product.

The process of the present invention can be carried out through theemployment of apparatus as to be hereinafter described. Accordingly,such process will be further described in connection therewith. Suchapparatus broadly comprises delivery means providing the yarn or strandsby over end yarn delivery or unrolling delivery, heat treatment means,means for separating the strands or yarns, means for starting and, ifdesired, regulating the twist, and means for receiving the yarn. Inaddition, it is possible to provide an optional drawing means.

The means for regulating the twist are essential when the yarn issupplied by over end yarn delivery, because in such case, an unwindingtwist from the bobbin is added to or subtracted from the twist initiallygiven, depending on the direction of unwinding. Such means of regulationcan be of any suitable type, but advantageously they can be combinedwith means for separating the strands and for starting the twist.

Such a regulating means is preferably made up of a mobile spindlecarrying at least two arms arranged symmetrically in relation to saidspindle and provided, on their free ends, with passages for the yarn,said spindle being provided with means exerting a recall couple ofdetermined value opposing the twist couple of the yarn.

This spindle can be supported in any known way by mechanical, pneumaticor hydraulic means, but advantageously it is held in position by amagnetic element, solid therewith and exerting a repelling action onanother stationary magnetic element.

The recall couple can be exerted in any known way but preferably, it issimply caused by the action of a magnetic block, in an adjustableposition, located opposite a portion of the spindle of a magneticmaterial. It is then possible simply to regulate the value of the recallcouple, and accordingly, the twist imparted to the yarn, by regulatingthe distance of the block from the spindle, for example, by a simplemeans such as a cam device.

Thus, if the twist couple becomes greater than the recall couple, thespindle can turn so as to bring the twist couple to the value provided.

Finally, a driving whorl connected to a motor that is or is notprogrammed can be mounted on the mobile spindle. This can make itpossible to vary the twist couple if a determined program is desired.

When the yarn is unrolled or when several yarns are supplied by over endyarn delivery, it is unnecessary to have a twist regulator. Accordingly,in a preferred embodiment of the present invention, means for separatingthe strands or yarns are then made up of a hollow spindle carrying atits upper end at least a pin that is solid with the inside wall of thespindle, and presenting a free end so as to separate the hollow space ofthe spindle into two compartments freely communicating with one another,said hollow spindle turning in a stationary socket and being driven by amotor that is or is not programmed Due to this device for separating theyarns, it is easy to introduce and separate the elementary ends (strandsor yarns), which, therefore, makes it possible to work continuously.

In accordance with the present invention, the means for thermallytreating the yarns or strands can be any conventional type well known inthe art. Generally, however, the heating means can comprise any suitableheating box which allows for contact heating or can simply compriseheating plates. It is certainly within the scope of the presentinvention, however, to employ other conventional and equivalent heatingmeans such as a liquid bath, etc. Again, the particular heat treatmentmeans employed in accordance with the present invention is not criticaland any conventional means well known in the art can be advantageouslyutilized.

The present invention, including the product, process and apparatus willnow be illustrated by reference to the drawings wherein FIG. 1 is adiagrammatic view illustrating one embodiment of the apparatus of thepresent invention;

FIG. 2 is a detailed view of a self-regulating device for support andmagnetic control in accordance with the apparatus of the presentinvention;

FIG. 3 is a further diagrammatic view of an alternate embodiment inaccordance with the present invention;

FIG. 4 is an enlarged view of the separating device used in the mountingof FIG. 3;

FIG. 5 is a top view of a hollow spindle employed in the separatingdevice of FIG. 4;

FIG. 6 is a diagrammatic view of the mounting used in accordance withthe present invention to determine the value of the twist couple; and

FIG. 7 diagrammatically illustrates the yarn obtained in accordance withthe present invention.

According to the apparatus diagrammatically illustrated in FIG. 1, ayarn 1 with two ends is unrolled from a bobbin 2, then is drawn betweentwo rollers 3 and 4 before passing on a heating plate 5 and being woundon a cop 6 by a ring system 7 and a runner 8. To embody the processaccording to the present invention, the yarn is previously given adetermined number of turns between the drawing system and receivingdevice in a manner well known in the art. Yarn 1 being thus twisted, thetwo strands are separated and a stationary pin 9 is introduced betweenthem to block the twist. The twist located up line from this pin isdefinitely blocked at this point, and shoved back as the yarn advanceswhen the delivery and drawing organs are in movement. Heating plate 5makes it possible then to seat this twist. It is often preferable tosupply this yarn by over end yarn delivery. In this case, the unwindingtwist is increased or decreased (depending on the direction ofunwinding), by the twist which has been given, and which is located inthe heating zone. It is then necessary to provide a twist regulatingdevice.

A first solution consists in adding a programming system to thecompensating pin to maintain a constant twist coefiicient. Such asolution unfortunately requires considerable means. Another simplersolution consists in providing an autoregulating system. Such a deviceis illustrated by FIG. 2.

Yam 1 passes into eyelets 11 and 11' of the two separating arms 12 and12 carried by a hollow spindle 13 and goes through the latter in theaxis. This hollow spindle is held by two magnets 14 and 15. Magnet 14 issolid with spindle 13 while magnet 15 is stationary. These two magnetsexert on one another a repulsion force that supports spindle 13.

The accumulated twist has a tendency to make spindle 13 turn which isbraked by the action of a magnetic block 16, so that only anaccumulation of normal twist coming from the spinning bobbin puts it inmovement in the direction of the untwisting until the untwistingcouplemagnetic brake balance is achieved again. Of course, it ispossible to use any other equivalent means such as hydraulic orpneumatic support.

It is also obvious that it is possible to draw the yarn directly afterspinning, then to apply to it the process according to the invention, inwhich case this self-regulating device is unnecessary.

Another solution, as shown in the following examples, consists inpulling two yarns instead of one (see FIG. 3). In this way, theunwinding twist in coming from the spinning bobbin is no longer harmful,because the combined play of the two yarns assures its compensation.

In FIG. 3, two yarns 17 and 18 are supplied by over end yarn deliveryfrom two bobbins l9 and 20. These yarns are brought through two yarnguides 21 and 22, a drawing device comprising a yarn guide, for example,of the barbin type 23, two rollers 24 and 25, a pin 26, and a system ofdrawing rollers 27 and 28. The twist is blocked, due to a roller 29. Theyarn, to which a suitable initial twist is given, then passes on aheating plate 30 before passing through a separating device shown byFIG. 4. This device comprises a hollow spindle 31, provided at its upperpart with a separating pin 32. Spindle 31 turns inside a stationarycylinder 33 and is driven at its lower part by a belt 34 moved by amotor 35.

The yarns then pass into a slackening device comprising three rollers36, 37 and 38 before being received on cops 39 and 40.

A preferential arrangement of the separating pin is shown in FIG. 5.This separating pin 32 divides spindle 31 into areas connected by anopen space, which allows the assembly to go into the spindle, thenseparates it, instead of being arranged to introduce the two ends intotheir sector one after the other. This arrangement of the separating pinon the inside of spindle 31 is, therefore, particularly advantageous.

Having described the product, process and apparatus of the presentinvention, the same will now be more clearly illustrated by reference tothe following specific examples.

EXAMPLES 1 TO 9 Drawing rate winding rate Drawing rate X The followingcharacteristics were found for the yarn that was obtained:

Curling, defined by the number of undulations per 2.54 cm of yarn andthe twist couple expressed in turns per meter. This twist couple ismeasured in the follow ing way:

A length of 2 meters is taken, one of the ends being attached to astationary point A. The yarn is made to pass into a hook at a point Blocated one meter lower and then the other end is attached to point A(see FIG. 6). The yarn is released at point B by withdrawing the hook.Under the action of the residual twist, the yarn begins to curl up. Withany known type of torsiometer, all that is then required is to calculatethe binding twist of the two strands of yarn.

The results obtained are summed up in the following table:

J. 554-55 Sp 3 Fol 134-5 41-50 Aug RUPPERT(. 9250)DAYS Undula- 10 PlateInitial Slack- Drawing tion, Twist temp, twist ening s end, curling]couple, Ex C. in t./m. rate m. min. 2.54 cm. turns/m.

All of these yarns are deformed so as to present a more or lesspronounced bean shape.

Examples 1 and 2 illustrate the influence of the twist on curling.

Examples 3 to 9 made at normal treating temperatures in texturation showthe influence of the temperature and also illustrate the flexibility ofthe process which makes it possible, by varying temperature and twist tohave a more or less curled yarn and presenting more or less the twistcouple effect. FIG. 7 gives the appearance of the yarn obtained inExample 7. A section on a bundle of yarns and not on a single yarn wasmade for microscopic examination.

Examples 7, 8 and 9 show the fact of increasing the drawing speed leadsto a reduction of residual couple, although the latter even at 300m/min. remains considerable. It can be noted that the speeds forproducing this yarn are much greater than those of the processes ofmechanical texturation.

EXAMPLE 10 The operating conditions used were identical with those ofthe previous examples, including the choice of yarn, only the length ofthe heating plate was changed from 400 mm to mm. The temperature was 280C. The initial twist on t/m was 4,000 t/m, the slackening rate was 3percent and the drawing rate was 100 m/ min.

A yarn was then obtained presenting 10 undulations per em but withoutresidual twist couple.

Example 10 shows the importance of the length of the heating organ.Moreover, on a circular double drop 420 needle frame, with a diameter of3% inches, a stocking was knitted from a yarn according to Examples 7, 8and 9 by alternating a row of S twist yarn with a row of Z twist yarn.The stocking obtained was fixed at 100 C for 20 minutes, then dyed at 85C for 3 hours and postformed at 125 C for 90 seconds.

The following test was then made. On a stocking coming from the frame, alength of 100 mm. was marked off on the stocking laid flat in theslackened state. Then this stocking was slipped on to a cylindrical tube80 mm. in diameter, before any heat treatment; to its free end wassuspended a 1 kg weight and the elongation in the raw state wasmeasured. This same measurement was repeated on the postformed stocking,which gives the elongation in the postformed state. Finally, the loadwas removed and the stocking was again placed fiat and the distanceseparating the initial 100 mm markings was measured, making it possibleto determine the percentage of return.

8 This test was app-lied to stockings knitted under the abovementionedconditions, with the yarns according to Examples 7, 8 and 9.

The following results were found:

Percent raw Postfornied Percent Example elongation elongation return Itshould be noted that these stockings present a great elasticity and aconsiderable elastic return force, because stocking was slipped on to acylindrical tube mm in back to a length very close to its initiallength.

EXAMPLE 1 1 With the aid of a device similar to that used in the aboveexamples, but where the drawing part has been eliminated, two yarns ofethylene polyterephthalate 22 dtex/monostrand, previously drawn at arate of 4.1, were treated by feeding them at a speed of m/min., and bypulling them at the outlet of the separation device with slackeningrollers at a speed of 99 m/min. A heating plate with a length of 25 mmwas brought to a temperature of 250 C. The initial twist given was 5,000turns/m.

A yarn with a section deformed in the shape of a slightly ovalized beanwas obtained with the number of undulations per inch equal to 4 and theresidual twist couple of 80 turns/m.

Further, the foam effect is measured in the following way:

A skein of 2,666 dtex, 132 strands, of this yarn was soaked for 10 min.in water at 70 C, then dried in the slackened state, and left 12 hoursin an atmosphere at 22 C and 65 70 percent humidity.

The skein was then subjected for 2 minutes to a load of 600 g. A firstlength L of the skein was then measured. This load was removed andreplaced by a load of 4.8 g. which was left for an hour. The new lengthL of the skein is then measured.

The foam effect is given by the ratio L/ 1 X 100.

In this case a value of was found, which corresponds to a slightelasticity of the yarn.

It can be seen from the above examples that the process and apparatus ofthe present invention allow for the production of a novel textileproduct having greater advantages over those previously utilized in theprior art. In this regard, the textile products produced in accordancewith the present invention are extremely flexible and the same can bemade at speeds which are greater than those employed in standardtexturation. Thus, the process of the present invention is particularlyinteresting industrially since it is economical and leads to theproduction of articles which have an attractive appearance and apleasant touch.

What is claimed is:

1. A process for the production of continuous filaments of thermoplasticmaterial comprising:

a. creating an initial twist in an individual strand having at least twofilaments or in an assembly of a number of strands, said strands havinga high count per strand and said assembly comprising a small number ofstrands;

b. thermally treating the twisted material of (a);

c. blocking said twist at a point located immediately after said thermaltreatment; and

d. separating the filaments of the twisted individual strand or thestrands of the assembly of strands at said point while maintaining saidmaterial in a plastic state until subsequent to said separation andwinding the filaments or strands.

2. The process of claim 1 wherein the degree of twist of the strands orassembly of strands varies.

record in the patented file of this patent or the original patent.

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